Nitrocompounds



June 21, 1966 w. L. GILLILAND .NITROCOMPOUNDS Filed Sept. 16, 1963 United States Patent 3,257,470 NITROCOMPOUNDS William L. Gilliland, 420 Lingle Ave., Lafayette, Ind. Filed Sept. 16, 1963, Sen-No. 309,352

12 Claims. (Cl. 260-644) This application is a continuation-in-part of Serial No. 71,137 filed Jan. 15, 1949, now US. Patent No. 3,103,882.

My invention relates to certain improvements in the use of high explosives and to the composition of certain explosives for use, for example, in a device such as that of parent application Serial Number 71,137 filed January 15, 1949, issued September 17, 1963, as Patent Number 3,103,882.

These improvements are described under principal headings relating to the following subjects:

(1) An explosive cartridge provided with a device for maintaining the liquid explosive therein under a definite pressure, which can be arranged to reach any desired value of pressure.

(2).An arrangement of explosives in a cartridge of a form that may be similar to the device described in application Serial No. 761,779, filed July 18, 1947, now abandoned, in which two or more explosives of diflerent velocities of detonation are combined in a particular non-homogeneous arrangement. When detonation is initiated at a selected point in this body of explosive, the detonation wave assumes a particular shape which it does not have in moving through a mass of homogeneous explosive, this shape being produced by the difference in the velocity of the detonation wave in different parts of the explosive mass. The wave shape can be made such as to result in the more rapid passage of the detonation wave along the shaped face of a shaped charge. This in turn results in a blast of greater penetrating power from the shaped charge, especially when a metal liner is used on the shaped face.

(3) A means for obtaining from liquid explosives a greater uniformity of action and a more powerful blast than is otherwise attainable. This means consists in filling the cartridge completely full of liquid, without the conventional air space above it, and then, as by means of a screw device, placing the explosive under pressure. The pressure control may be facilitated by a flexible accordionlike drum, which yields as the fluid pressure increases, and which compensates for the very slight shrinkage of the rigid case due to hydrostatic pressure.

(4) The components of the liquid explosive mixtures, which are themselves liquids, and which are termed oxygen sources in patent application Serial No. 761,780, filed July 18, 1947, now abandoned, as tetranitromethane, nitroform (M.P. 26 C.), tetranitroethylene and trinitrofluoromethane, as well as the fuel components, also liquids, are degassed prior to mixing by exposing them for -a time to ultrasonic vibrations of suitable frequency and intensity. This may be done by immersing a glass flask of such liquid in an oil bath in which a vibrating quartz piezo crystal is maintained. Liquids so treated show a diminished sensitivity to shock, and a more uniform and powerful detonation than before treatment.

(5) A list of suitable explosive substances and combinations for use in the foregoing devices which include some new and some uncommon explosive materials for which new methods of preparation are given in detail. In general, the description in patent application Serial No. 761,780 is applicable to the explosives here described, and the mixture of a fuel and an oxygen source in accordance therewith is suggested. It is expected that the patent which will result directly from the present application will be directed especially to one explosive in this list, the diammonium salt of tetranitroethane and its method of manufacture.

Although the law requires a full and exact description ice of at least one form of the invention, such as that which follows, it is, of course, the purpose of a patent to cover each new inventive concept therein no matter how it may later be disguised by variations in form or additions of further improvements; and the appended claims are intended to accomplish this purpose by particularly pointing out the parts, improvements or combinations in which the inventive concepts are found.

FIG. 1 is a somewhat diagrammatic representation of one embodiment of the invention. FIGS. 2 and 3 are diagrams of the wave propagation of explosives.

Explosives cartridge with internal pressure In FIG. 1 a rigid watertight metal container 1, capable of withstanding the external hydrostatic pressures under which it will operate and reasonable internal pressure, is fitted with a suitably constructed head 2 which carries an electric detonator 3 with an insulated electric lead 4, the other detonator terminal being grounded. The head 2 is secured to case 1 with an intervening compressible washer by a milled coupler ring 5 (or flatsided ring) threaded to the case 1 and adjustable to increase or de-.

crease the volume inside container 1. When container 1 is filled with liquid 9, a very small increase or decrease of volume will result in a large increase or decrease of internal pressure. In order that the pressure range may be kept within lower limits than might otherwise be the case, a metal tube 6 with flexible side walls, of an accordion-like construction, entirely closed and empty or airfilled, is inserted in the space below the detonator. 3, so that an increase in pressure is partially compensated by the shrinkage of the volume of this closed metal tube 6.

The principle involved in this feature of internal pressure is simply that of providing a rigid solid container in the form of a metallic shell, and having no air pocket or space in the main path of thedetonation wave to act as a cushion to give any degree of relief to the pressures induced after detonation has begun. While it is true that the container offers very little effective resistance to the detonation pressures after the detonation is under way, and the air cushion affords essentially no relief to such pressures, nevertheless in the instant of first formation of the detonation wave, and the beginning of the explosive process, these two factors may .play a part and it is favorable to greater brisance to have rigid confinement under tension.

Degasified liquid high explosives Preferably all liquid explosives used here or elsewhere are degassed. The principle involved is in essence similar to the pressure feature just described. It is desirable to remove the minute air bubbles present in the liquid explosive, and the dissolved gases which may form such bubbles. Since the liquid explosives contemplated for use in this device include the ones described in application Serial No. 761,780, and are essentially tetranitromethane or other oxygen sources, mixed in approximately zero oxygen balance with benzonitrile or other selected fuel substances, it is possible to degasify the liquid oxygen source and the liquid fuel substance separately before mixing. The liquids are simply exposed for a short time to ultrasonic vibrations of a comparatively low frequency, so that the gas evolution takes place. The two liquids are mixed and used as soon as practical afterwards. This procedure results in diminished sensitivity to shock of the mixtures, with consequent greater safety in handling and in improved penetration by the shaped charge or explosive force in any event when the explosive is fired. It-is thus seen that degasified liquid explosives of very high brisance maybe provided by this invention.

Annular wave source for shaped charge The horizontal tube-like portion of case 1 terminates in a void 7, which is formed at least in part by an internal metal shell 8 that excludes the explosive liquid 9 and is given any customary or suitable shape for producing the shaped charge effect. This shell, being fluid tight, maintains a void space between the explosive and the outer end 10 of the cartridge, which is intended to be placed against the casing of the oil well casing (or other object) which is to be perforated. This arrangement is very similar to that described in copending patent ap plication Serial No. 761,779, except for the facilities for producing internal pressure. According to a feature of the invention covered in Patent 3,103,882 issued September 17, 1963, a deflector 11 is provided. It may be formed to include a void with walls that are considerably heavier than those intended for producing shaped charge effects, and which in fact serves to obstruct the passage of the detonation wave over the greater part of the crosssectional area of explosive, permitting it to pass only at the space 12, which space is in the form of a thin ring or annulus, so that the detonation wave passes 12 not as the section of a spherical surface with its center at the point of detonation (detonator 3), but as a ring whose outer diameter is the inner wall of container 1 at the section 12, and whose inner diameter is the outside of metal container 11. The purpose of the obstruction 11 is the creation of a detonation wave of this form. The consequences of this annular detonation 'wave are shown in FIG. 2.

As seen by reference to wave front 13, which would be annular in form, the wave progressing from annular section 12 would have a component of its movement inwardly toward the longitudinal axis of the tubular portion 14 of casing 1. This would have two advantages.

' When the wave has no inward component the explosive force tends to spread radially outwardly with considerable dissipation. The inward component minimizes this effect and directs a greater proportion of the explosive force in the desired direction parallel to the longitudinal axis. The other advantage is in connection with the shaped face 16. The unusual effectiveness of such shaped faces appears to be in part due to the sudden impingement of inwardly directed forces emanating from this face. The rapidity with which this effect builds up can be increased by a wave shape which passes more rapidly along the shaped face. If we assume an extreme situation of a wave propagated from a point 18 even with the apex of the shaped face 16, this wave would reach the apex and many other points on the shaped surface somewhat beyond the apex substantially simultaneously. The wave emanating from section 12 is not this extreme but it nevertheless reaches the successive points beyond the apex more quickly after reaching the apex than the spherical waves in prior art shaped charge explosives. The converging of the waves along the center axis as they emanate from the section 12 tends to produce a strong forward component to cooperate with the inwardly directed forces from the shaped face to produce the desired extreme piercing power. 'The diameter of section 12, its longitudinal spacing from the shaped face, and the shape of the face can be varied to give maximum effects.

Concave wave front obtained by difierential explosives A wave shape which maintains adequate forward force along the longitudinal axis and at the same time conforms more closely to the shape of the shaped face will more fully develop the possibilities of the shaped charge effect. This can be accomplished by a non-homogeneous arrangement of explosives having different velocities of their detonation waves, with the explosive detonating more rapidly arranged annularly around that which detonates more slowly. This is illustrated in FIG. 3.

In FIG. 3 an explosive charge, as for a cartridge 1, is represented as including an outer cylinder A of one explosive and a core B of another explosive. They preferably form one rod without a sharp demarcation between them. The outside surface of the rod is essentially pure A while the center is essentially pure B. Such a composition might be obtained by inserting a close fitting cylinder of compressed B into a tube of compressed A, and then causing a partial fusion of the two and intermingling at the interface by heat. General separation and centering can be maintained by centrifugal force produced by spinning the cylinder about its axis if A is denser than B. For A one may use hexanitromannitol and for B pentaerythritol tetranitrate. In this case heat is applied with extreme caution and not above the point where A becomes fluid. A and B are so chosen that the detonation velocity of A is greater than that of B, with the result that when detonation is initiated the wave 21 that moves along the rod from left to right may start as the usual type of generally spherical wave but progresses to a generally conical or parabolic shape, as suggested in FIG. 3. As a consequence of its concave shape, when wave 21 reaches the metallic conical liner 22 on the shaped face which produces the shaped charge effect, it will pass over the surface of this liner more rapidly than would a fiat wave. For example, in the illustration, when the periphery of the wave front moves from a to b, the wave traverses the liner from a to b. This more rapid passage may result either in a larger portion of the liner metal being present in the high velocity jet and a smaller portion in the slug, or in a pose may conform to the interior 9 of the container 1 shown in FIG. 1, and may be employed either with or without the metallic obstruction 11 intended to produce an annular detonation.

The lines 21 are not intended to be exact representations of the wave shapes. Indeed, these may be varied widely by choice of materials and varying degrees and extents of intermingling from the original interface. More than two explosives may be used.

The concave wave shape may be useful even without the shaped face; and with a flat face (preferably having a liner-like flat plate in contact therewith) may produce results similar to that of a shaped face.

As in FIG. 1, it may be desirable, with some explosives at least, to maintain a pressure inside the container, as by a liquid explosive into which the detonator is adjustably projected by turning ring 5. In fact, the solid central core may be omitted if desired and the same liquid The explosive materials suggested for use in the devices described in this application include the list of combinations set forth in application Serial No. 761,780, and certain additional explosive substances. The methods of preparation are given for some of these which are new or unfamiliar, and in some case where these methods of preparation are of sufiicient importance to warrant, claims are drawn to cover them. The appropriate use and method of employment of each substance is indicated.

The additional substances are:

1) The ammonium salt of nitroform as an oxygen source.

(2) The methylammonium salt of nitroform.

(3) The diammonium salt of tetranitroethane.

(4) Tetranitroethylene.

(5) 2,2,3,3-tetranitrobutanediol-1,4.

(6) 2,2,3,3-tetranitrobutanediol-1,4 dinitrate (7) 2,2,2-trinitroethanol.

(8) 1,1,1,2-tetranitroethane.

(9) 2,2,2-trinitroethanol nitrate.

(10) 2,2,2-trinitr0ethyldimethylolnitromethane.

(11) Dipropargyl.

(l2) Nitromalonitrile.

( l3 Dinitromalonitrile.

Those which are high explosives suitable, alone, for use in FIG. 1 are (in the above list) 2, 3, 5, 7, 8 and 10.

,Those which are suitable for use as oxygen sources as described in my application Serial No. 761,780, in combination with a fuel are 4, 6, 7, 8 and 9. No. 1 might be considered in this class, although it is not as rich in oxygen.

Those which are suitable for fuels as mentioned in the preceding paragraph and more fully in said application are 11, 12 and 13.

The same numbers are used in the following discussion.

(1) The ammonium salt of nitroform is well known and is a solid explosive of moderate stability and power, and in industrial production should be reasonably cheap. It is also an oxygen source.

(2) The methylammonium salt of nitroform is a new composition of matter, produced by the action of methylamine on an equivalent quantity of nitroform in water solution. It is quite soluble in and readily crystallized from water. It is a very powerful explosive and its use is highly recommended.

(3) Those compounds containing the l,l,2,2 tetranitro grouping are generally prepared from the dipotassium salt of tetranitroethane, and the preparation of this latter substance will be described in detail:

One hundred grams dinitrodibromomethane with or without a solvent, for example, 60 ml. methanol, are placed in a 1,000 ml. tall beaker, fitted with a motordriven stirrer and cooled in a salt-ice bath. A solution of 155 gm. potassium cyanide in 230 ml. Water is added slowly from a dropping funnel, the temperature being maintained below 30 C., in practice between C. and C. in spite of the developed heat. After the addition is complete, the mixture is stirred for half an hour, and then filtered through a sintered glass funnel and the precipitate washed with about ml. water. The material is sucked dry on the filter and dried for two hours on a porous plate. It is then dissolved in 250 ml. boiling water to which 0.5 gram potassium carbonate has been previously added, and the resulting solution filtered hot. The clear yellow or amber filtrate is cooled quickly in an ice bath, and the voluminous crystalline precipitate filtered off, washed with a little water and dried. Yield, about 55 grams of the dipotassium salt of l,l,2,2-tetranitroethane.

In an alternative procedure for forming-this substance, 1,2-dinitroethane may be used as a starting material. The disodium salt of 1,2-dinitroethane in water solution,

'with the theoretical amount of. bromine yields an insoluble dibromide. This dibromide is removed and suspended in a 50% solution of methyl alcohol in water, and treated with a water Solution of potassiumnitrite and potassium cyanide in equivalent quantities. The dipotassium salt of tetranitroethane is formed as described above and is purified in the same way. In this procedure, chlorine may be used in place of bromine-if desired.

If the dipotassium salt of tetranitroeth-ane so prepared is added cautiously, in portions, to a solution of an equivalent quantity of ammonium chloride in anhydrous liquid ammonia, potassium chloride and the diammonium salt of tetranitroethane are formed. The potassium chloride is filtered OH, and washed with anhydrous ammonia to extract residual ammonium salt. The ammonium salt so produced is a yellow crystalline solid, and is an explosive of great power. Its use is recommended.

An alternate laboratory method consists in adding aqueous ammonium chloride in equivalent amount to the disilver salt of tetranitroethane, when the insoluble silver chloride which is formed may be filtered oil, and the diammonium salt recovered by evaporation.

(4) Tetranitroethylene may be conveniently prepared by the electrolysis of the water solution of the dipotassium salt of tetranitroethane, forming in oily drops at the anode.

It may be readily prepared from the disilver salt of tetranitroethane by adding any reagent that has a marked affinity for silver. For example, by grinding the silver salt with metallic mercury, or with mercuric chloride, or with stannous chloride when silver chloride and mercurous chloride or tin is formed. A simple method of pre aration is the grinding together of equivalent quantities of dry mercuric chloride and the dry silver salt of tetranitroethane until a very intimate mixture is secured and then removing the oil by slow distillation in vacuo. Tetranitroethylene is a colorless, slowly volatile oil with a characteristic musk-like odor.

One-half of its oxygen content is available to burn other fuel substances and its use is suggested and recommended as an oxygen source in the sense that this term is used in application Serial No. 761,780. The fuel substances with which it may be mixed as an oxygen source are the organic compounds which are soluble in tetranitroethylene and which are ordinarily burnable in air. It is also suggested for use to be added to any high explosive to bring the resulting explosive mixture toward zer-o oxygen balance so as to produce a much more powerful and brisant product.

(5) If 10 grams of the finely powdered dipotassium salt of tet-ranitroethane be added slowly to a mixture of 8 ml. 40% aqueous formaldehyde, 8 ml. water and 10 ml. of phosphoric acid, at temperatures below 0 C., and if the reaction is properly initiated at the beginning of the addition, 2,2,3,3-tetranitrobutanediol-1,4 is produced. This substance is an excellent explosive.

(6) If the diol just described is slowly added to nitric acid (1.52 density) or to a nitric-sulphuric acid mixture, at temperatures of 0 C. to 10 C., the dinitrate is produced. This may be used either as an explosive or as an v oxygen source.

(7) If 10 grams of potassium nitroform be added slowly to a mixture of 8 ml. 40% aqueous formaldehyde, 8 ml. of water and 10 ml. 85% phosphoric acid, at temperatures between 10 C. and 20 C., an oily layer separates which is 2,2,2-trinitroethanol. Upon dewatering (as by pumping) large crystals of this substance separate. It is an excellent explosive and may be used as an oxygen source also.

(8) If 2,2,2-trinitroet-hanol is treated with phosphorous trichloride or tribromide, a chloride or bromide results. If this chloride or bromide is treated with silver nitrite, or more simply with an aqueoussolution of potassium cyanide and potassium nitrite, the potassium salt of 1,l,l,2-tetranitroethane is formed. The pure 1,1,1,2-tetranitroethane may be liberated from this salt with phosphoric acid. It is an explosive but more useful as an oxygen source.

(9) if 2,2,2trinitroethanol is treated with nitric acid of density 1.5-2, or with a mixture of nitric and sulphuric acids, with cooling .to 0 C. there is produced a nitrate. This nitrate may be used as an oxygen source in combination with fuel materials or in combination with other oxygen sources and fuel materials.

(10) If 10 grams of 1,1,1,2-tetranitroethane is slowly added to 10 rnl. of 40% aqueous formaldehyde with stirring and cooling, the diol of the structure 2,2,2-trinitroethyldimethylolnitromethane is produced. This is an explosive compound.

(11) Dipropargyl, C H an isomer of benzene, is a well-known substance, described adequately in the chemical literature. It is recommended as a fuel substance for combination with oxygen sources to produce explosive materials.

(12) If ammonium fulminurate is mixed intimately with an excess of phosphorous pentoxide, and allowed to stand 24 hours, there may be distilled from the mixture under reduced pressure nitromalonitrile, which is a useful fuel-substance, particularly when mixed with substances The previous application said potassium fulminurate by obvious error.

containing a percentage content of oxygen greater than that of nitromalonitrile, such as trinitroacetonitrile, nitroform or tetranitroethylene.

(13) Nitromalonitrile produced as indicated may be nitrated with nitric acid of a density of 1.52 or with nitric and sulphuric acid to form dinitromalonitrile, which is an explosive. As in the case of nitromalonitrile, that dinitromalonitrile may be mixed with trinitroacetonitrile, nitroform or tetranitroethylene, or other substance containing a percentage content of oxygen higher than nitromalonitrile to produce an explosive of very great power.

In connection with the above explosive mixtures, and more particularly with the mixtures described in application Serial No. 761,780, it is frequently desirable to use tetranitromethane as an oxygen source. This material is frequently prepared by some operators in an impure and dangerous state. It may be brought to a high state of purity and stability by means of nitric acid. The following is a specific example of a procedure for such purification.

One kilogram of freshly prepared tetranitromethane is poured into one kilogram of pure nitric acid having a density of 1.50 or higher. It dissolves at once with a cooling of the mixture. The resultant solution is allowed to stand for at least a day and preferably longer, and is then poured into very clean ice and water, and the dense layer of tetranitrometh-ane separated and washed thoroughly with water. It is then dried with anhydrous margnes'ium sulphate and filtered through a sintered glass funnel.

.This same method of nitric acid treatment is useful in cleaning up any contaminated aliphatic-nitro compound that does not react with nitric acid. In the case of products from the Victor Meyer synthesis, it is most useful in removing nitrites and other undesirable side reaction products. Nitroethane, dinitroethane and numerous other compounds may be purified by this procedure.

The disclosure of my application, Serial Number 76 1,- 780, filed July 18, 1947, is hereby incorporated herein by reference.

I claim:

1. An explosive comprising the diammonium salt of tetranitroethane.

2. The process of forming the diammonium salt of 1,1,2,2-tetranitroethane which comprises reacting the dipotassium salt of 1,1,2,2-tetr anitroethane with ammonium chloride in anhydrous liquid ammonia.

3. The method of providing a gas-free liquid high explosive comprising supersonically degasifying each of two liquids less explosive in nature which when mixed form said high explosive, and thereafter mixing said liquids.

4. An explosive comprising the methylammonium salt of nitroform.

5. An explosive comprising tetranitroethylene.

6. The method of forming the dipotassium salt of 1,1, 2,2-tetranitroethane which comprises reacting dinitrodibromomethane with potassium cyanide.

7. The process of forming the dipotassium salt of' 1,1, 2,2-tetranitroethane which comprises converting 1,2-dinitroethane into its sodium salt, reacting the resulting product with bromine, and reacting the bromine-treated product with an aqueous solution containing potassium nitrite and potassium cyanide.

8. The method of producing tetranitroethylene which comprises electrolyzing the water solution of the dipotassium salt of 1,1,2,2-tetranitroeth-ane.

9. The process of forming tetranitroethylene which comprises reacting the disilver salt of 1,1,2,2-tetranitroethane with a reagent selected from the group consisting of metallic mercury, mercuric chloride and stannous chloride.

10. The method of purifying tetranitromethane which comprises dissolving said tetranitromethane in nitric acid, allowing said solution to stand for at least a day and then mixing the solution with water to separate the tetranitromethane from the nitric acid.

11. The method of purifying an aliphatic nitro compound which does not react with nitric acid which comprises dissolving said compound in nitric acid, allowing said solution to stand for at least a day, and then mixing the solution with water to separate the aliphatic nitro compound from the nitric acid.

12. As a new compound, tetranitroethylene.

References Cited by the Examiner UNITED STATES PATENTS 2,616,919 11/ 1952 Lawrence 149-88 2,963,515 12/ 1960 Feuer et al. 260-644 2,993,768 7/1961 Holzl 149-88 3,040,105 6/1962 Tawney 260644 3,101,379 8/1963 Gallaghan et al. 260644 LEON D. ROSDOL, Primaly Examiner.

CARL D. QUARFORTH, L. DEWAYNE RUTLEDGE,

Examiners.

B. R. PADGETT, L. A. SABASTIAN,

Assistant Examiners. 

1. AN EXPLOSIVE COMPRISING THE DIAMMONIUM SALT OF TETRANITROETHANE. 